The ALS-associated co-chaperone DNAJC7 mediates neuroprotection against proteotoxic stress by modulating HSF1 activity
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PROVIDER: PRJNA1220708 | ENA |
REPOSITORIES: ENA
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Project description:The degeneration of neurons in patients with amyotrophic lateral sclerosis (ALS) is commonly associated with accumulation of misfolded, insoluble proteins. Heat shock proteins (HSPs) are central regulators of protein homeostasis as they fold newly synthesized proteins and refold damaged proteins. Heterozygous loss-of-function mutations in the DNAJC7 gene that encodes an HSP co-chaperone were recently identified as a cause for rare forms of ALS, yet the mechanisms underlying pathogenesis remain unclear. Using mass spectrometry, we found that the DNAJC7 interactome in human motor neurons (MNs) is enriched for RNA binding proteins (RBPs) and stress response chaperones. MNs generated from iPSCs with the ALS-associated mutation R156X in DNAJC7 exhibit increased insolubility of its client RBP HNRNPU and associated RNA metabolism alterations. Additionally, DNAJC7 haploinsufficiency renders MNs increasingly susceptible to proteotoxic stress and cell death as a result of an ablated HSF1 stress response pathway. Critically, expression of HSF1 in mutant DNAJC7 MNs is sufficient to rescue their sensitivity to proteotoxic stress, while postmortem ALS patient cortical neurons exhibit a reduction in the expression of HSF1 pathway genes. Taken together, our work identifies DNAJC7 as a crucial mediator of HNRNPU function and stress response pathways in human MNs and highlights HSF1 as a therapeutic target in ALS.
2025-02-11 | GSE289053 | GEO
Project description:Heat Shock Factor 1 (HSF1) is best known as the master transcriptional regulator of the heat-shock response (HSR), a conserved adaptive mechanism critical for protein homeostasis (proteostasis). Combining a genome-wide RNAi library with an HSR reporter, we identified JMJD6 as an essential mediator of HSF1 activity. In follow-up studies, we found that JMJD6 is itself a non-canonical transcriptional target of HSF1 which acts as a critical regulator of proteostasis. In a positive feedback circuit, HSF1 binds and promotes JMJD6 expression, which in turn reduces HSP70 R469 monomethylation to disrupt HSP70-HSF1 repressive complexes resulting in enhanced HSF1 activation. Thus, JMJD6 is intricately wired into the proteostasis network where it plays a critical role for cellular adaptation to proteotoxic stress.
2024-07-18 | GSE270672 | GEO
Project description:Heat Shock Factor 1 (HSF1) is best known as the master transcriptional regulator of the heat-shock response (HSR), a conserved adaptive mechanism critical for protein homeostasis (proteostasis). Combining a genome-wide RNAi library with an HSR reporter, we identified JMJD6 as an essential mediator of HSF1 activity. In follow-up studies, we found that JMJD6 is itself a non-canonical transcriptional target of HSF1 which acts as a critical regulator of proteostasis. In a positive feedback circuit, HSF1 binds and promotes JMJD6 expression, which in turn reduces HSP70 R469 monomethylation to disrupt HSP70-HSF1 repressive complexes resulting in enhanced HSF1 activation. Thus, JMJD6 is intricately wired into the proteostasis network where it plays a critical role for cellular adaptation to proteotoxic stress.
2024-07-18 | GSE270671 | GEO
Project description:Stress responses are a key feature of normal physiology and are usurped by cancer cells to ensure enhanced protein synthesis for growth, to compensate for genomic instability, and to protect cancer cells from therapy induced stress. Heat shock factor-1 (HSF1) is a major stress-response transcription factor, and its activity is markedly enhanced in cancer. Stress induces HSF1 conformational changes and post-translational modifications, leading to assembly of active HSF1 trimers that bind DNA to control target gene expression. Although the function of HSF1 in transcription is relatively well-known, the mechanisms leading to HSF1 activation and enhanced stress response in tumours are unclear. To investigate whether HSF1 is a primary sensor of proteotoxic stress in vivo, we studied the range of conditions that can cause HSF1 activation in vitro and in cells, and conditions that prevent its activation. We show that purified recombinant HSF1 adopts a stable monomeric conformation in vitro. Heat stress caused a conformational change and the assembly of HSF1 trimers. Conditions leading to protein denaturation, including heat stress, crowding, Hsp90 inhibition, or proteasome inhibition, all directly lead to HSF1 activation. In contrast, HSF1 activation in vivo is prevented by proteosynthesis inhibition, which reduces the amount of denatured proteins in the cell. These results establish that HSF1 is a direct sensor of proteotoxic stress, independent of post-translational modification, where abrupt environmental changes that cause protein denaturation simultaneously induce a conformational change in monomeric HSF1 leading to its activation. This mechanism explains the universal ability of cells to respond to proteotoxic stress and trigger a protective response when increased chaperone activities are required to restore homeostasis.
2024-08-14 | PXD037662 | Pride
Project description:The heat shock response is an ancient and ubiquitous program allowing organisms to survive adverse environmental conditions. In S. cerevisiae, three transcription factors, Hsf1, Msn2 and Msn4, are thought to regulate the stress response. While Msn2/4 can be deleted, Hsf1 is essential. By combining the depletion of Hsf1 with the deletion of Msn2 and Msn4, we were able to switch off the central stress response. We show that the transcription factors Hsf1 and Msn2/4 follow different strategies and regimes: Whereas Msn2/4 are responsible for a broad metabolic response, Hsf1 triggers a direct chaperone response to stabilize and repair unfolded proteins. Exposure of cells lacking Msn2/4 and Hsf1 to thermal stress resulted in massive protein aggregation. Comparison with wildtype yeast revealed that among the proteins rescued by the stress response are many essential proteins.
2024-01-31 | PXD024352 | Pride
Project description:Diverse cellular insults converge on activation of the heat shock factor 1 (HSF1), which regulates the proteotoxic stress response to maintain protein homoeostasis. HSF1 regulates numerous gene programmes beyond the proteotoxic stress response in a cell-type- and context-specific manner to promote malignancy. However, the role(s) of HSF1 in immune populations of the tumour microenvironment remain elusive. Here, we leverage an in vivo model of HSF1 activation and single-cell transcriptomic tumour profiling to show that augmented HSF1 activity in natural killer (NK) cells impairs cytotoxicity, cytokine production, and subsequent anti-tumour immunity. Mechanistically, HSF1 directly binds and regulates the expression of key mediators of NK cell effector function. This work demonstrates that HSF1 regulates the immune response under the stress conditions of the tumour microenvironment. These findings have important implications for enhancing the efficacy of adoptive NK cell therapies and for designing combinatorial strategies including modulators of NK cell-mediated tumour killing. This SuperSeries is composed of the SubSeries listed below.
2021-02-26 | GSE167552 | GEO
Project description:An HSF1-JMJD6-HSP feedback circuit promotes cell adaptation to proteotoxic stress [RNA-Seq]
| PRJNA1127665 | ENA
Project description:An HSF1-JMJD6-HSP feedback circuit promotes cell adaptation to proteotoxic stress [ChIP-Seq]
| PRJNA1127661 | ENA
Project description:Although HSF1 is known to play an important role in regulating the cellular response to proteotoxic stressors, little is known about the structure and function of the HSF1 signaling network under both stressed and unstressed conditions. In this study, we used a combination of chromatin immunoprecipitation (ChIP) microarray analysis and time course gene expression microarray analysis with and without siRNA-mediated inhibition of HSF1 comprehensively identify genes directly and indirectly regulated by HSF1 and examine the structure of the extended HSF1 signaling network. Correlation between promoter binding and gene expression was not significant for all genes bound by HSF1 suggesting that HSF1 binding per se is not sufficient for expression. However, the correlation with promoter binding was significant for genes identified as HSF1-regulated following siRNA knockdown allowing the identification of direct transcriptional targets of HSF1. Among promoters bound by HSF1 following heat shock, a gene ontology (GO) analysis showed significant enrichment only in categories related to protein folding. In contrast, analysis of the extended HSF1 signaling network showed enrichment in a variety of categories related to protein folding, anti-apoptosis, RNA splicing, ubiquitination and others, highlighting a complex transcriptional program directly and indirectly regulated by HSF1.,SUBMITTER_CITATION: Genome-wide analysis of human HSF1 signaling reveals a transcriptional program linked to cellular adaptation and survival Authors: Todd J. Page, Devanjan Sikder, Longlong Yang, Linda Pluta, Russell D. Wolfinger, Thomas Kodadek, and Russell S. Thomas Journal: Molecular Biosystems 2:627-639
2007-06-22 | E-GEOD-3697 | biostudies-arrayexpress
Project description:The heat shock response is a universal transcriptional response to proteotoxic stress orchestrated by heat shock transcription factor Hsf1 in all eukaryotic cells. Despite over 40 years of intense research, the mechanism of HSF1 activity regulation remains poorly understood at a molecular level. In metazoa Hsf1 trimerizes upon heat shock through a leucin-zipper domain and binds to DNA. How Hsf1 is dislodged from DNA and monomerized remained enigmatic. Here, using purified proteins we demonstrate that unmodified trimeric Hsf1 is dissociated from DNA in vitro by Hsc70 and DnaJB1. Hsc70 binds to multiple sites in Hsf1 with different affinities. Hsf1 trimers are monomerized by successive cycles of entropic pulling, unzipping the triple leucinezipper. Starting this unzipping at several protomers of the Hsf1 trimer results in faster monomerization. This process directly monitors the concentration of Hsc70 and DnaJB1. During heat shock adaptation Hsc70 first binds to a high affinity site in the transactivation domain leading to partial attenuation of the response and subsequently, at higher concentrations, Hsc70 removes Hsf1 from DNA to restore the resting state.
2020-06-22 | PXD017406 | Pride